What can cause curling when applying a maintenance coating?

Curling in the context of applying a maintenance coating can occur due to the use of an incompatible existing coating system. When a maintenance coating is applied over an existing coating that has different chemical properties, such as differing resin types or curing mechanisms, it can lead to adhesion issues. This incompatibility can result in stresses that cause the new coating to curl away from the surface as it dries or cures, leading to aesthetic and performance problems.

In contrast, while factors such as high humidity levels, insufficient surface cleaning, and poor application techniques can influence the overall performance of a coating, they typically do not directly lead to curling in the same way that incompatibility does. High humidity may cause issues with drying times or adhesion, but it doesn't inherently cause physical curling of the film. Insufficient surface cleaning can lead to poor adhesion leading to flaking or peeling, rather than curling, and poor application technique may affect application uniformity but is less likely to cause the specific issue of curling.